import {Message} from 'element-ui'
const ORIGINAL_THEME = '#409EFF'
/**
 * 主题颜色设置
 */
class Theme {
  chalk
  async setThemeStyle(val) {
    if (!this.chalk) {
      const url = `/theme/index.css`
      await this.getCSSString(url, 'chalk')
    }
    const oldVal = this.chalk ? val : ORIGINAL_THEME
    if (typeof val !== 'string') return
    const themeCluster = this.getThemeCluster(val.replace('#', ''))
    const originalCluster = this.getThemeCluster(oldVal.replace('#', ''))
    // console.log(themeCluster, originalCluster)

    const $message = Message({
      message: '  Compiling the theme',
      customClass: 'theme-message',
      type: 'success',
      duration: 0,
      iconClass: 'el-icon-loading'
    })

    const getHandler = (variable, id) => {
      return () => {
        const originalCluster = this.getThemeCluster(ORIGINAL_THEME.replace('#', ''))
        const newStyle = this.updateStyle(this[variable], originalCluster, themeCluster)

        let styleTag = document.getElementById(id)
        if (!styleTag) {
          styleTag = document.createElement('style')
          styleTag.setAttribute('id', id)
          document.head.appendChild(styleTag)
        }
        styleTag.innerText = newStyle
      }
    }
    const chalkHandler = getHandler('chalk', 'chalk-style')

    chalkHandler()

    const styles = [].slice.call(document.querySelectorAll('style'))
      .filter(style => {
        const text = style.innerText
        return new RegExp(oldVal, 'i').test(text) && !/Chalk Variables/.test(text)
      })
    styles.forEach(style => {
      const { innerText } = style
      if (typeof innerText !== 'string') return
      style.innerText = this.updateStyle(innerText, originalCluster, themeCluster)
    })

    // this.$emit('change', val)

    $message.close()
  }

  updateStyle(style, oldCluster, newCluster) {
    let newStyle = style
    oldCluster.forEach((color, index) => {
      newStyle = newStyle.replace(new RegExp(color, 'ig'), newCluster[index])
    })
    return newStyle
  }

  getCSSString(url, variable) {
    return new Promise(resolve => {
      const xhr = new XMLHttpRequest()
      xhr.onreadystatechange = () => {
        if (xhr.readyState === 4 && xhr.status === 200) {
          this[variable] = xhr.responseText.replace(/@font-face{[^}]+}/, '')
          resolve()
        }
      }
      xhr.open('GET', url)
      xhr.send()
    })
  }

  getThemeCluster(theme) {
    const tintColor = (color, tint) => {
      let red = parseInt(color.slice(0, 2), 16)
      let green = parseInt(color.slice(2, 4), 16)
      let blue = parseInt(color.slice(4, 6), 16)

      if (tint === 0) { // when primary color is in its rgb space
        return [red, green, blue].join(',')
      } else {
        red += Math.round(tint * (255 - red))
        green += Math.round(tint * (255 - green))
        blue += Math.round(tint * (255 - blue))

        red = red.toString(16)
        green = green.toString(16)
        blue = blue.toString(16)

        return `#${red}${green}${blue}`
      }
    }

    const shadeColor = (color, shade) => {
      let red = parseInt(color.slice(0, 2), 16)
      let green = parseInt(color.slice(2, 4), 16)
      let blue = parseInt(color.slice(4, 6), 16)

      red = Math.round((1 - shade) * red)
      green = Math.round((1 - shade) * green)
      blue = Math.round((1 - shade) * blue)

      red = red.toString(16)
      green = green.toString(16)
      blue = blue.toString(16)

      return `#${red}${green}${blue}`
    }

    const clusters = [theme]
    for (let i = 0; i <= 9; i++) {
      clusters.push(tintColor(theme, Number((i / 10).toFixed(2))))
    }
    clusters.push(shadeColor(theme, 0.1))
    return clusters
  }
}
export default new Theme()
